CN117242294A

CN117242294A - Optical system, illumination system, display system, and moving object

Info

Publication number: CN117242294A
Application number: CN202280029046.9A
Authority: CN
Inventors: 上水和平; 高田和政; 藤田胜
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2021-04-28
Filing date: 2022-03-08
Publication date: 2023-12-15
Also published as: WO2022230370A1; US20240045206A1; JPWO2022230370A1

Abstract

The optical system includes a light guide member, a prism, and a plurality of light controllers. The light guide member has an incident surface on which light is incident, and first and second surfaces facing each other. The second surface of the light guide member is an outgoing surface of the light. The prism is provided on the first surface and reflects light passing through the inside of the light guide member toward the second surface. The plurality of light control bodies are positioned between the light source and the incident surface. The plurality of light controllers control light output from the light source and incident on the incident surface. The plurality of light control bodies are each provided with an incidence lens. The plurality of light control bodies respectively make light which is incident on the incidence lens from the light source incident on the incidence surface. At least two light control bodies among the plurality of light control bodies respectively have directions of optical axes of light incident on the incident surface different from each other.

Description

Optical system, illumination system, display system, and moving object

Technical Field

The present disclosure relates generally to optical systems, illumination systems, display systems, and mobile bodies. More specifically, the present disclosure relates to an optical system, an illumination system, a display system, and a moving body that control light incident from an incident surface and emitted from an emission surface.

Background

Patent document 1 discloses an image display device (display system) that projects a virtual image into a subject space. The image Display device is a Head-Up Display (HUD) device for an automobile. The projection light, which is image light emitted from a HUD device (optical system) for an automobile in an instrument panel, is reflected by a windshield and directed toward a driver as a viewer. Thus, the user (driver) can visually recognize an image such as a navigation image as a virtual image, and visually recognize that the virtual image is superimposed on a background such as a road surface.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2017-142491

Disclosure of Invention

An optical system according to one embodiment of the present disclosure includes a light guide member, a prism, and a plurality of light control bodies. The light guide member has an incident surface on which light is incident, and first and second surfaces facing each other. The second face of the light guide member is an exit face of light. The prism is provided on the first surface and reflects light passing through the inside of the light guide member toward the second surface. The plurality of light control bodies are located between the light source and the incident surface. The plurality of light controllers control light output from the light source and incident on the incident surface. The plurality of light control bodies are each provided with an incidence lens. The plurality of light controllers respectively make the light which is incident to the incidence lens from the light source incident to the incidence surface. At least two light controllers among the plurality of light controllers respectively make different directions of optical axes of light incident on the incident surface.

Drawings

Fig. 1A is a side cross-sectional view showing an outline of an optical system according to an embodiment.

Fig. 1B is a schematic diagram of the region F1 of fig. 1A enlarged.

Fig. 2 is a side sectional view showing an outline of a light control body of the optical system as above.

Fig. 3A is a top cross-sectional view for explaining the direction of the optical axis of light in the optical system as above.

Fig. 3B is a side sectional view for explaining the direction of the optical axis of light in the optical system as above.

Fig. 4 is a perspective view showing an outline of the optical system described above.

Fig. 5 is an explanatory view of a display system using the same optical system.

Fig. 6 is an explanatory view of a mobile body provided with the display system as above.

Fig. 7A is a top view of the optical system as above.

Fig. 7B is a front view of the optical system as above.

Fig. 7C is a bottom view of the optical system as above.

Fig. 7D is a side view of the optical system as above.

Fig. 8A is a schematic diagram of the region A1 of fig. 7C enlarged.

Fig. 8B is a sectional view taken along line B1-B1 of fig. 8A.

Fig. 9 is a plan view schematically showing the luminance distribution of the emitted light in the optical system of the comparative example.

Fig. 10 is a plan view schematically showing the luminance distribution of the emitted light in the optical system of the embodiment.

Fig. 11 is a front view showing an outline of a light control body of the optical system as above.

Fig. 12 is a side sectional view for explaining an optical path in a light control body of the optical system as above.

Fig. 13 is a side sectional view for explaining an optical path in a light control body of the optical system as above.

Fig. 14 is a front view showing an outline of a light control body according to modification 1.

Detailed Description

In the image display device described in patent document 1, there is a possibility that brightness of an image visually recognized by a user is uneven.

The present disclosure has been made in view of the above, and an object thereof is to provide an optical system, an illumination system, a display system, and a moving object, which can reduce unevenness in brightness of an image visually recognized by a user.

An optical system 100 (see fig. 1A), an illumination system 200, a display system 300 (see fig. 5), and a moving object B1 (see fig. 6) according to an embodiment of the present disclosure will be described in detail with reference to the drawings. The embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. In addition to the embodiment and the modification, various modifications may be made according to the design or the like without departing from the scope of the technical idea of the present disclosure. The drawings described in the following embodiments are schematic, and the ratio of the sizes and thicknesses of the components in the drawings does not necessarily reflect the actual dimensional ratio. The following embodiments (including modifications) may be implemented in appropriate combination.

(1) Summary of the inventionsummary

First, an outline of the optical system 100 according to the present embodiment and the illumination system 200 using the optical system 100 will be described with reference to fig. 1A to 4.

The optical system 100 according to the present embodiment (see fig. 1A and 1B) has a function of controlling light incident from the incident surface 10 and emitting the light from the emitting surface (the second surface 12). As shown in fig. 1A and 1B, the optical system 100 includes a light guide member 1, a plurality of light control bodies 2, and a prism 3.

The optical system 100 together with the light source 4 constitutes an illumination system 200. In other words, the illumination system 200 according to the present embodiment includes the optical system 100 and the light source 4.

The light source 4 outputs light incident on the incident surface 10. When the optical system 100 includes a plurality of light control bodies 2, light from the light source 4 is not directly incident on the light guide member 1, but is incident on the light guide member 1 through the light control bodies 2, which will be described later in detail. In other words, the light emitted from the light source 4 is incident on the incident surface 10 (of the light guide member 1) through the light control body 2.

As described above, in the present embodiment, the optical system 100 includes the plurality of light control bodies 2 in addition to the light guide member 1 and the prism 3. The plurality of light control bodies 2 are located between the light source 4 and the incidence surface 10 of the light guide member 1, and control light output from the light source 4 and incident on the incidence surface 10. In particular, in the present embodiment, the light guide member 1 and the plurality of light controllers 2 are integrated as an integrally molded product. In other words, in the present embodiment, the light guide member 1 and the plurality of light control bodies 2 are integrally molded articles, and are in an integral inseparable relationship. In other words, the plurality of light control bodies 2 are continuous without seams with respect to the incident surface 10 of the light guide member 1, and the light guide member 1 and the plurality of light control bodies 2 are seamlessly integrated. Therefore, in the present embodiment, the incident surface 10 of the light guide member 1 is a predetermined "virtual surface" inside the integrated product of the light guide member 1 and the plurality of light control bodies 2, and is not accompanied by a solid body.

In the present embodiment, the light guide member 1 has an incident surface 10 on which light is incident, and first and second surfaces 11 and 12 facing each other. The second face 12 is the light exit face. The prism 3 is arranged on the first face 11. The prism 3 reflects the light passing through the inside of the light guide member 1 toward the second surface 12.

As shown in fig. 2, in the present embodiment, the plurality of light controllers 2 each include an incident lens 21. The plurality of light control bodies 2 make light incident from the light source 4 to the incidence lens 21 incident on the incidence surface 10, respectively.

The incidence lens 21 has a main incidence surface 211 and a sub incidence surface 212. The main incidence surface 211 is arranged to face the light source 4. The sub-incident surface 212 faces the normal L21 of the main incident surface 211. Here, the normal L21 of the main incidence surface 211 is, for example, the normal of the main incidence surface 211 at the tip portion (peak portion of the dome) if the main incidence surface 211 is dome-shaped. The normal line L21 of the main incidence plane 211 is a "virtual line" and is not accompanied by a solid body. The sub-incident surface 212 is located at least partially around the main incident surface 211. Here, as shown in fig. 1A, an optical axis P1 of the light (first incident light LT 1) incident from the light source 4 coincides with a normal L21 of the main incident surface 211. Further, the optical axis P1 is parallel to the second surface 12.

Further, the plurality of light controllers 2 can control the direction of the optical axis P1 of the first incident light LT1, respectively. Specifically, as shown in fig. 3A and 3B, the first incident light LT1 having the optical axis P1 is incident on the incident surface 10 as the second incident light LT2 having the optical axis P2 by the plurality of light controllers 2, respectively. Here, the optical axis P1 and the optical axis P2 may intersect or may be parallel. In addition, the term "crossing" as used herein is synonymous with an angle formed by the optical axis P1 and the optical axis P2 being greater than 0 degrees. In addition, as will be described later in detail, the first incident light LT1 is nearly parallel light by the light control body 2, and is incident on the incident surface 10 as the second incident light LT 2.

In the present embodiment, at least two light controllers 2 among the plurality of light controllers 2 are different from each other in the direction of the optical axis P2 of the second incident light LT2 incident on the incident surface 10. For example, in the present embodiment, the optical system 100 includes 7 light controllers 2 (light controllers 2A to 2G). The light control bodies 2A to 2G are located between the plurality of light sources 4 (light sources 4A to 4G) corresponding one to one and the incidence surface 10 of the light guide member 1, respectively. The light control bodies 2A to 2G are arranged in the width direction of the light guide member 1 (the direction in which the light sources 4A to 4G are arranged in fig. 4). The directions of the optical axes P2 (optical axes P2A to P2G) of the second incident light LT2 (second incident light LT2A to second incident light LT 2G) respectively entering the incidence plane 10 from the light control body 2A to the light control body 2G are different from each other.

The first incident light LT1 (first incident light LT1A to first incident light LT 1G) is incident on the light control bodies 2A to 2G from the light sources 4A to 4G, respectively. At this time, as shown in fig. 3A and 3B, the directions of the optical axes P1 (optical axes P1A to P1G) of the first incident light LT1A to first incident light LT1G are all equal and parallel to each other. The optical axes P1A to P1G are parallel to the second surface 12 and perpendicular to the incident surface 10. Here, the first incident light LT1A to the first incident light LT1G are converted into parallel light by the incident lenses 21 provided in the light control bodies 2A to 2G, and are incident on the incident surface 10 as second incident light LT2A to second incident light LT2G having the optical axis P2 (optical axis P2A to optical axis P2G), respectively. The optical axis P1 and the optical axis P2 may intersect or may be parallel to each other. For example, as shown in fig. 3A and 3B, the optical axis P2A of the second incident light LT2A is located on the optical axis P1A of the first incident light LT1A, and the optical axis P1A is parallel to the optical axis P2A. The optical axes P2A to P2G intersect each other. In other words, the orientations of the optical axes P2A to P2G are different from each other.

As described above, the optical system 100 can control the luminance distribution of the outgoing light emitted from the outgoing surface (the second surface 12) by controlling the directions of the optical axes P2A to P2G by the light control bodies 2A to 2G, respectively, as shown in fig. 3A and 3B, for example. The directions of the optical axes P2A to P2G shown in fig. 3A and 3B are examples, and the directions of the optical axes P2A to P2G can be appropriately changed so that the light emitted from the second surface 12 has a desired luminance distribution. Here, the outgoing light is planar light formed by the second incident light LT2A to the second incident light LT2G reflected by the prism 3, and the luminance distribution of the outgoing light is the light quantity distribution of the outgoing light on the second surface 12.

(2) Detailed description

The optical system 100, the illumination system 200 using the optical system 100, the display system 300 using the illumination system 200, and the moving object B1 according to the present embodiment will be described in detail below with reference to fig. 1A to 13.

(2.1) precondition

In the following description, the width direction of the light guide member 1 (the direction in which the plurality of light sources 4 are arranged in fig. 4) is referred to as the "X-axis direction", and the depth direction of the light guide member 1 (the direction in which light from the light sources is incident on the incident surface 10 in fig. 1A) is referred to as the "Y-axis direction". In the following description, the thickness direction of the light guide member 1 (the direction in which the first surface 11 and the second surface 12 are aligned in fig. 1A) is referred to as "Z-axis direction". The X-axis, Y-axis, and Z-axis defining these directions are orthogonal to each other. The arrows in the drawings indicating the "X-axis direction", "Y-axis direction" and "Z-axis direction" are merely indicated for the sake of illustration, and are not accompanied by an entity.

The term "extraction efficiency" as used herein refers to the ratio of the amount of the outgoing light emitted from the second surface 12 (outgoing surface) of the light guide member 1 to the amount of the second incident light LT2 incident on the incident surface 10 of the light guide member 1. That is, if the relative ratio of the light quantity of the outgoing light emitted from the second surface 12 of the light guide member 1 with respect to the light quantity of the second incoming light LT2 that enters the incident surface 10 of the light guide member 1 becomes large, the light extraction efficiency becomes high (becomes large). As an example, if the light quantity of the second incident light LT2 incident on the incident surface 10 of the light guide member 1 is "100", the light extraction efficiency of the light in the light guide member 1 is 10% if the light quantity of the outgoing light outgoing from the second surface 12 of the light guide member 1 is "10".

In addition, the "optical axis" referred to in the present disclosure means an imaginary light ray that is representative of a light beam passing through the entire system. As an example, the optical axis P1A of the first incident light LT1A incident from the light source 4A to the light control body 2A coincides with the rotational symmetry axis of the first incident light LT 1A.

Further, "parallel" as referred to in the present disclosure means a relationship in a range in which an angle between the two is converged to a degree of several degrees (for example, less than 2 degrees) except for a case where the two are substantially parallel, in other words, the two are strictly parallel.

In addition, the term "orthogonal" as used in the present disclosure refers to a relationship in which an angle between the two is in a range of a few degrees (for example, less than 2 degrees) on the basis of 90 degrees, except for a case where the two are substantially orthogonal to each other, in other words, the two are strictly orthogonal to each other.

(2.2) display System

First, the display system 300 will be described with reference to fig. 5 and 6.

As shown in fig. 5, the illumination system 200 according to the present embodiment forms a display system 300 together with the display 5. In other words, the display system 300 according to the present embodiment includes the illumination system 200 and the display 5. The display 5 receives light emitted from the illumination system 200 to display an image. The "image" referred to herein is an image that is displayed so as to be visually recognizable to the user U1 (see fig. 6), and may be a graphic, a symbol, a letter, a number, a pattern, a photograph, or the like, or a combination thereof. The images displayed by the display system 300 include moving images (moving images) and still images (still images). Further, the "moving image" includes an image composed of a plurality of still images obtained by slow imaging (time-lapse photography) or the like.

As shown in fig. 6, the display system 300 according to the present embodiment forms a mobile body B1 such as an automobile together with the mobile body B11. In other words, the moving object B1 according to the present embodiment includes the display system 300 and the moving object body B11. The mobile body B11 mounts the display system 300. In the present embodiment, the moving body B1 is a motor vehicle (passenger vehicle) driven by a person as an example. The moving body B1 may be an automated guided vehicle that can travel by automated driving. In this case, the user U1 who views the image displayed by the display system 300 is an occupant of the mobile body B1, and in the present embodiment, as an example, it is assumed that a driver (driver) of the motor vehicle as the mobile body B1 is the user U1.

In the present embodiment, the Display system 300 is used, for example, for a Head-Up Display (HUD) mounted on the mobile body B1. The display system 300 is used to display driving assistance information related to, for example, speed information, status information, and driving information of the mobile body B1 in the field of view of the user U1. Examples of the driving information of the mobile body B1 include information on navigation showing a travel route and the like, and information on ACC (Adaptive Cruise Control: adaptive cruise control) for keeping the travel speed and the inter-vehicle distance constant.

As shown in fig. 5 and 6, the display system 300 includes an image display unit 310, an optical system 320, and a control unit 330. The display system 300 further includes a housing 340 that accommodates the image display unit 310, the optical system 320, and the control unit 330.

The case 340 is made of, for example, a molded product of synthetic resin. The case 340 accommodates the image display unit 310, the optical system 320, the control unit 330, and the like. The case 340 is attached to the instrument panel B13 of the mobile body B11. The light reflected by a second mirror 322 (described later) of the optical system 320 is emitted to a reflecting member (windshield B12) through an opening portion of the upper surface of the case 340, and the light reflected by the windshield B12 is condensed in an eye movement range (eyebox) C1. The reflecting member is not limited to the windshield B12, and may be realized by a combiner or the like disposed on the instrument panel B13 of the mobile body B11, for example.

According to such a display system 300, the user U1 visually recognizes a virtual image of a space projected in front of (outside of) the mobile body B1 through the windshield B12. The "virtual image" as referred to in the present disclosure refers to an image in which, when light emitted from the display system 300 is diffused by a reflecting member such as the windshield B12, the diffused light is coupled so that an object is actually present. Therefore, the user U1 driving the moving body B1 overlaps with the actual space extending forward of the moving body B1, and visually recognizes an image as a virtual image projected by the display system 300. In short, the display system 300 according to the present embodiment displays a virtual image as an image. The images (virtual images) that can be displayed by the display system 300 include a virtual image E1 superimposed along the traveling surface D1 of the moving body B1 and a virtual image stereoscopically drawn along a plane PL1 orthogonal to the traveling surface D1.

The image display unit 310 includes a housing 311. The image display unit 310 has a function of displaying a stereoscopic image by reproducing Light emitted from an object in an image in a plurality of directions to stereoscopically display a Light Field (Light Field) of the object. The method of displaying the virtual image of the object stereoscopically depicted by the image display unit 310 is not limited to the light field method. The image display unit 310 may adopt the following parallax method: by projecting images having parallax to each other to the left and right eyes of the user U1, the user U1 can visually recognize a virtual image of the stereoscopic image-drawn object.

The image display unit 310 includes the display 5 and the illumination system 200 including the optical system 100. The display 5 is, for example, a liquid crystal display or the like, and receives light emitted from the illumination system 200 to display an image. In other words, the illumination system 200 emits light from the back of the display 5 toward the display 5, and the light from the illumination system 200 is transmitted through the display 5, whereby the display 5 displays an image. In other words, the illumination system 200 functions as a backlight of the display 5.

The image display unit 310 includes a housing 311. An illumination system 200 including the optical system 100 and the light source 4 and the display 5 are accommodated in the housing 311. The illumination system 200 and the display 5 are held by the housing 311. Here, the display 5 is disposed along the upper surface of the housing 311, and one surface of the display 5 is exposed from the upper surface of the housing 311. The illumination system 200 is disposed below the display 5 in the housing 311, and outputs light from below the display 5 toward the display 5. Thus, the upper surface of the housing 311 forms a display surface 312 on which an image is displayed.

The image display unit 310 is accommodated in the case 340 with the display surface 312 facing a first mirror 321 (described later). The display surface 312 of the image display unit 310 is a shape (for example, a rectangular shape) that matches the range of the image projected to the user U1, in other words, the shape of the windshield B12. A plurality of pixels are arranged in an array on a display surface 312 of the image display unit 310. The plurality of pixels of the image display unit 310 emit light under the control of the control unit 330, and an image is displayed on the display surface 312 by light output from the display surface 312 of the image display unit 310.

The image displayed on the display surface 312 of the image display unit 310 is emitted to the windshield B12, and the light reflected by the windshield B12 is condensed in the eye movement range C1. In other words, the image displayed on the display surface 312 is visually recognized by the user U1 whose viewpoint is located within the eye movement range C1 through the optical system 320. At this time, the user U1 visually recognizes a virtual image of a space projected in front of (outside of) the mobile body B1 through the windshield B12.

The optical system 320 condenses the light output from the display surface 312 of the image display unit 310 in the eye movement range C1. In the present embodiment, the optical system 320 includes, for example, a first mirror 321 that is a convex mirror, a second mirror 322 that is a concave mirror, and a windshield B12.

The first mirror 321 reflects the light output from the image display unit 310, and makes it incident on the second mirror 322. The second mirror 322 reflects the light incident from the first mirror 321 toward the windshield B12. The windshield B12 reflects the light incident from the second mirror 322 and is incident to the eye movement range C1.

The control unit 330 includes, for example, a computer system. The computer system is mainly composed of one or more processors and one or more memories as hardware. The functions of the control unit 330 (for example, functions of the drawing control unit 331, the image data creating unit 332, the output unit 333, and the like) are realized by one or more processors executing programs recorded in one or more memories or storage units 334 of the computer system. The program is recorded in advance in one or more memories or storage sections 334 of the computer system. The program may be provided through a telecommunication line or may be recorded on a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive readable by a computer system.

The storage unit 334 is implemented by a non-transitory recording medium such as a rewritable nonvolatile semiconductor memory. The storage unit 334 stores a program or the like executed by the control unit 330. As described above, the display system 300 is configured to display driving assistance information related to the speed information, the situation information, the driving information, and the like of the mobile body B1 in the field of view of the user U1. Accordingly, the kind of virtual image displayed by the display system 300 is predetermined. Further, the storage unit 334 stores image data for displaying virtual images (a virtual image E1 of the object to be planar drawn and a virtual image of the object to be stereoscopic drawn) in advance.

The drawing control unit 331 receives detection signals from various sensors 350 mounted on the moving body B1. The sensor 350 is, for example, a sensor for detecting various information used in the advanced driving system (ADAS: advanced Driver Assistance System). The sensor 350 includes, for example, at least one of a sensor for detecting a state of the moving body B1 and a sensor for detecting a state of the surroundings of the moving body B1. The sensor for detecting the state of the moving body B1 includes, for example, a sensor for measuring the vehicle speed, the temperature, the remaining fuel, or the like of the moving body B1. The sensor for detecting the state of the surroundings of the moving body B1 includes an image sensor that photographs the surroundings of the moving body B1, millimeter wave radar, liDAR (Light Detection and Ranging ), or the like.

The drawing control unit 331 obtains one or more image data for displaying information related to the detection signal from the storage unit 334 based on the detection signal input from the sensor 350. Here, when the image display unit 310 displays a plurality of types of information, the drawing control unit 331 obtains a plurality of image data for displaying the plurality of types of information. The drawing control unit 331 obtains positional information on a position where the virtual image is displayed in the object space where the virtual image is displayed, based on the detection signal input from the sensor 350. Then, the drawing control unit 331 outputs the image data and the positional information of the virtual image of the display object to the image data creating unit 332.

The image data creation unit 332 creates image data for displaying a virtual image of the display object based on the image data and the position information input from the drawing control unit 331.

The output unit 333 outputs the image data created by the image data creation unit 332 to the image display unit 310, and causes the display surface 312 of the image display unit 310 to display an image based on the created image data. The display system 300 displays an image (virtual image) by projecting the image displayed on the display surface 312 onto the windshield B12. In this way, the image (virtual image) displayed by the display system 300 is visually recognized by the user U1.

(2.3) optical System

Next, the optical system 100 will be described with reference to fig. 1A to 4 and fig. 7A to 10.

In the present embodiment, the optical system 100 includes a light guide member 1, a plurality of light control bodies 2 (light control bodies 2A to 2G), and a plurality of prisms 3. That is, the optical system 100 according to the present embodiment includes a plurality of light control bodies 2 and a plurality of prisms 3.

In the present embodiment, the optical system 100 forms the illumination system 200 together with the light sources 4A to 4G. That is, the illumination system 200 according to the present embodiment includes the optical system 100 and the light sources 4A to 4G.

Since the plurality of light sources 4 (light sources 4A to 4G) have a common configuration, the configuration for describing one light source 4 is similar to that of the other light sources 4 unless otherwise specified below.

The light source 4 is a solid-state light-emitting element such as a light-emitting diode (LED: light Emitting Diode) element or an Organic Electro-Luminescence (OEL) element. In the present embodiment, the light source 4 is a chip-shaped light emitting diode element as an example. Such a light source 4 emits light with a certain area on the surface (light emitting surface) in practice, but it is desirable to be able to view a point light source that emits light from a point on the surface. Therefore, the following description will be given assuming that the light source 4 is an ideal point light source.

In the present embodiment, as shown in fig. 2, the light source 4 is arranged so as to face the incident surface 10 of the light guide member 1 with a predetermined interval. The light control body 2 is located between the light source 4 and the incidence surface 10 of the light guide member 1.

In the present embodiment, the light control body 2 is integrated with the light guide member 1. The term "integral" as used in the present disclosure refers to a manner in which a plurality of elements (portions) can be physically handled as one body. In other words, the integration of a plurality of elements means that the plurality of elements are integrated into one, and can be handled as one component. In this case, the plurality of elements may be in an integral and inseparable relationship as in an integrally molded product, or the plurality of elements separately produced may be mechanically joined by welding, adhesive bonding, caulking, or the like, for example. That is, the light guide member 1 and the light control body 2 may be integrated in an appropriate manner.

More specifically, in the present embodiment, as described above, the light guide member 1 and the light control body 2 are integrated as an integrally molded product. In other words, in the present embodiment, the light guide member 1 and the light control body 2 are integrally molded articles, and are in an integral inseparable relationship. Therefore, as described above, the incident surface 10 of the light guide member 1 is a predetermined "virtual surface" inside the integrated product of the light guide member 1 and the light control body 2, and is not accompanied by a solid body.

Here, as shown in fig. 4, the light sources 4A to 4G are arranged at predetermined intervals along the X-axis direction. The light sources 4A to 4G correspond to the plurality of light control bodies 2A to 2G one by one. In other words, the light control bodies 2A to 2G are also arranged in the X-axis direction in the same manner as the light sources 4A to 4G. Here, the pitch of the light sources 4A to 4G in the X-axis direction is equal to the pitch of the light control bodies 2A to 2G.

The light guide member 1 is a member that takes in light from the light source 4 from the incident surface 10 into the light guide member 1, and guides the light to the exit surface, i.e., the second surface 12, through the inside of the light guide member 1, in other words, guides the light. In the present embodiment, the light guide member 1 is a molded product of a light-transmitting resin material such as an acrylic resin, and is formed in a plate shape. In other words, the light guide member 1 is a light guide plate having a certain thickness.

As described above, the light guide member 1 has the incident surface 10 on which light is incident, and the first surface 11 and the second surface 12 (exit surfaces) facing each other. The light guide member 1 further has an end surface 13 facing the incident surface 10.

Specifically, in the present embodiment, as shown in fig. 7A to 7D, the light guide member 1 has a rectangular plate shape, and the two surfaces facing each other in the thickness direction of the light guide member 1 are the first surface 11 and the second surface 12, respectively. Further, one of the four end faces (peripheral faces) of the light guide member 1 is an incident face 10. In other words, the light guide member 1 is formed in a rectangular shape in a plan view (as viewed from one of the Z-axis directions). Here, as an example, the light guide member 1 is formed in a rectangular shape having a smaller dimension in the Y-axis direction than in the X-axis direction. The two surfaces in the thickness direction (Z-axis direction) of the light guide member 1 constitute a first surface 11 and a second surface 12, respectively. Further, both sides in the short side direction (Y-axis direction) of the light guide member 1 constitute an incident surface 10 and an end surface 13, respectively.

In this way, one of the two end surfaces (left surface in fig. 1A) of the light guide member 1 facing each other in the Y-axis direction is the incident surface 10 on which the first incident light LT1 (first incident light LT1A to first incident light LT 1G) emitted from the light sources 4A to 4G, respectively, passes through the light control bodies 2A to 2G, respectively, and is made incident as the second incident light LT2 (second incident light LT2A to second incident light LT 2G). The two surfaces of the light guide member 1 facing each other in the Z-axis direction are a first surface 11 and a second surface 12, respectively. The first face 11 is the lower face in fig. 1A, and the second face 12 is the upper face in fig. 1A. The second surface 12 is an emission surface that emits light from the inside of the light guide member 1 to the outside. Therefore, the light guide member 1 emits surface light by the second incident light LT2 from the one end surface as the incident surface 10 and the second surface 12 as the exit surface.

In the present embodiment, the second surface 12 is a plane parallel to the X-Y plane. The incident surface 10 is a plane parallel to the X-Z plane. The "X-Y plane" as used herein is a plane including the X axis and the Y axis, and is a plane orthogonal to the Z axis. Similarly, the "X-Z plane" as referred to herein is a plane including the X axis and the Z axis, and is a plane orthogonal to the Y axis. The second surface 12 is a plane orthogonal to the Z axis, and the incident surface 10 is a plane orthogonal to the Y axis, so the second surface 12 and the incident surface 10 are orthogonal to each other.

On the other hand, the first face 11 is not parallel to the X-Y plane, but is a plane inclined with respect to the X-Y plane. In other words, the first face 11 and the incident face 10 are not orthogonal to each other. Specifically, the first face 11 is inclined with respect to the X-Y plane so as to approach the second face 12 as being away from the incident face 10. In other words, in the present embodiment, the first surface 11 and the second surface 12 are inclined to each other.

In the present embodiment, the end surface 13 is parallel to the incident surface 10, for example, as shown in fig. 1A.

In the present embodiment, the light distribution control unit 14 is provided on the second surface 12. The light distribution control section 14 includes a lens. As an example, the present embodiment includes a cylindrical lens. The light distribution control unit 14 will be described in detail in the column "(2.7) light distribution control unit". The light distribution control unit 14 is not necessarily configured for the optical system 100, and can be omitted appropriately.

The light control body 2 is arranged between the light source 4 and the incident surface 10 of the light guide member 1. The light control body 2 controls light output from the light source 4 and incident on the incident surface 10. In the present embodiment, the light control body 2 has a collimation function for making the first incident light LT1 output from the light source 4 nearly parallel light. That is, the light control body 2 is a collimator lens as follows: when the first incident light LT1 radially expanded from the light source 4 is incident, the first incident light LT1 is condensed toward the incident surface 10, thereby approaching parallel light. Here, the first incident light LT1 emitted from the light source 4 is incident on the incident surface 10 of the light guide member 1 through the light controller 2. Therefore, the first incident light LT1 from the light source 4 is controlled by the light control body 2 having the collimation function so that the spread angle becomes narrower, and is emitted as the second incident light LT2 toward the incident surface 10 of the light guide member 1. In the present embodiment, the description will be given assuming that the first incident light LT1 from the light source 4 as an ideal point light source is converted into the second incident light LT2 as an ideal parallel light by the light control body 2.

In the present embodiment, as shown in fig. 4, a plurality of light control bodies 2 (light control bodies 2A to 2G) are formed so as to be aligned in the X-axis direction at the end of the incident surface 10 constituting the light guide member 1. In other words, in the present embodiment, the light control body 2 is integrated with the light guide member 1. As described above, the light control bodies 2A to 2G correspond to the plurality of light sources 4 (light sources 4A to 4G) one to one, respectively. Therefore, the light control bodies 2A to 2G control the spread angles of the first incident light LT1 (first incident light LT1A to first incident light LT 1G) emitted from the corresponding light sources 4, respectively, and make the second incident light LT2 (second incident light LT2A to second incident light LT 2G) as parallel light incident on the incident surface 10, respectively. As described above, in the present embodiment, the directions of the optical axes P2 (optical axes P2A to P2G) of the second incident light LT2A to the second incident light LT2G are different from each other.

In the present embodiment, the angle formed by each of the optical axis P2A and the optical axes P2B to P2G is preferably greater than 0 degrees and 15 degrees or less, and more preferably 1 degree or more and 10 degrees or less. Details of the function of the light control body 2 are described in the column "(2.4) light control body".

The prism 3 is provided on the first surface 11, and reflects light passing through the inside of the light guide member 1 toward the second surface 12. In the present embodiment, a plurality of prisms 3 are provided on the first surface 11. The prism 3 is configured to totally reflect the incident second incident light LT 2. Of course, the prism 3 is not limited to the mode of totally reflecting the incident second incident light LT2, and may include a mode in which a part of the second incident light LT2 passes through the inside of the prism 3 and is emitted to the outside of the light guide member 1 without totally reflecting.

In the light guide member 1, most of the second incident light LT2 incident from the incident surface 10 is reflected by the prism 3 without being reflected at a portion other than the prism 3 in the first surface 11 or the second surface 12, and is emitted from the second surface 12. In other words, the light guide member 1 includes a direct optical path L1, and the direct optical path L1 allows the second incident light LT2 incident from the incident surface 10 to be directly reflected by the prism 3 and emitted from the second surface 12 as the emitted light.

In the present embodiment, the prism 3 is formed on the first surface 11 such that a cross section viewed from one of the X-axis directions is a triangular concave portion. The prism 3 is formed by, for example, processing the first surface 11 of the light guide member 1. As shown in fig. 1B, the prism 3 has a reflection surface 30 that reflects the second incident light LT2 incident through the inside of the light guide member 1 toward the second surface 12. Fig. 1B is a schematic end view of the region F1 of fig. 1A enlarged.

The angle θ1 formed by the reflective surface 30 and the first surface 11 (in other words, the inclination angle of the reflective surface 30) is an angle at which the incident angle θ0 of the second incident light LT2 incident on the reflective surface 30 is equal to or larger than a critical angle. In other words, the reflecting surface 30 is inclined with respect to the first surface 11 so that the incident second incident light LT2 is totally reflected. In the present embodiment, the inclination angle θ1 of the reflection surface 30 is set such that light totally reflected by the reflection surface 30 is incident in a direction perpendicular to the second surface 12, for example. In the present embodiment, a plurality of second incident lights LT2 (second incident lights LT2A to LT 2G) are incident on the first surface 11. Since the directions of the optical axes P2A to P2G of the second incident light LT2A to second incident light LT2G are different, the inclination angle θ1 is different depending on the plurality of areas A0 (areas a01 to a 07) where the second incident light LT2A to second incident light LT2G are respectively incident on the first surface 11. The direction in which the light totally reflected by the reflecting surface 30 is incident on the second surface 12 is not limited to the vertical direction, and the light totally reflected by the reflecting surface 30 may be incident obliquely on the second surface 12.

In the present embodiment, as shown in fig. 8A and 8B, the plurality of prisms 3 are arranged in a zigzag pattern on the first surface 11 as viewed from one side in the Z-axis direction. Here, fig. 8A is a schematic plan view of the region A1 of fig. 7C enlarged. Here, the area A1 is a part of the area a01 where the second incident light LT2A, which is the parallel light perpendicularly incident on the incident surface 10, is incident. Fig. 8B is a view schematically showing an end face of the line B1-B1 of fig. 8A. In fig. 8A, only a part of the first surface 11 is shown, but in practice, a plurality of prisms 3 are formed over substantially the entire area of the first surface 11.

Specifically, each prism 3 has a length in the X-axis direction, and a plurality of prisms 3 are arranged at intervals in the length direction (X-axis direction) thereof. The plurality of prisms 3 are also arranged at intervals in the Y-axis direction. When the first, second, and third rows … are formed by counting the rows of the plurality of prisms arranged in the X-axis direction from the incident surface 10 side in the Y-axis direction, the plurality of prisms 3 included in the even row and the plurality of prisms 3 included in the odd row are positioned so as to be offset from each other in the X-axis direction. Here, in the present embodiment, the plurality of prisms 3 included in the even-numbered columns and the plurality of prisms 3 included in the odd-numbered columns are arranged such that the respective longitudinal (X-axis) ends overlap each other in, for example, the Y-axis direction. According to such an arrangement, the plurality of prisms 3 are arranged without any gap in the X-axis direction as viewed from the incidence surface 10, and the second incident light LT2 incident into the light guide member 1 from the incidence surface 10 is reflected by any one of the plurality of prisms 3. The plurality of prisms 3 included in the even-numbered rows may be arranged such that the respective longitudinal ends (X-axis direction) have different slopes with respect to the Y-axis direction. The plurality of prisms 3 included in the odd-numbered columns may be arranged such that the respective longitudinal ends (X-axis direction) have different slopes with respect to the Y-axis direction.

In the present embodiment, as an example, the plurality of prisms 3 are all the same shape. Therefore, as shown in fig. 8B, among the plurality of prisms 3 arranged in the Y-axis direction, the inclination angle θ1 of the reflection surface 30 is the same angle. The size of the prism 3, such as the length direction of the prism 3 and the depth of the recess (in other words, the height of the prism 3) as the prism 3, is the same in the plurality of prisms 3. That is, in the present embodiment, the prisms 3 are arranged in plurality in the Y-axis direction. Here, in each of the areas a01 to a07, the plurality of prisms 3 have the same shape. Therefore, if the incident angle θ0 of the second incident light LT2 incident on the reflection surface 30 in the same area A0 is fixed, the orientation of the second incident light LT2 reflected by the reflection surface 30 of the prism 3 is the same even in the case where the light is incident on any prism 3 of the plurality of prisms 3. Accordingly, all of the second incident light LT2 reflected by the plurality of prisms 3 in the same area A0 can be made incident in the direction perpendicular to the second surface 12.

Further, as an example, the depth of the concave portion as the prism 3 (in other words, the height of the prism 3) is 1 μm or more and 100 μm or less. Similarly, as an example, the pitch in the Y-axis direction of the plurality of prisms 3 is 1 μm or more and 1000 μm or less. Specifically, the depth of the concave portion as the prism 3 in the region a01 is ten to several μm, and the pitch in the Y-axis direction of the plurality of prisms 3 is several hundred to ten μm.

The light emission principle of the optical system 100 according to the present embodiment will be described below with reference to fig. 1A, 3A, and 3B.

As shown in fig. 1A, for example, the first incident light LT 1A emitted from the light source 4A is controlled in expansion angle by the light controller 2A. Then, the second incident light LT2A having the controlled spread angle is emitted from the light controller 2A to the incident surface 10 of the light guide member 1. In the present embodiment, the second incident light LT2A emitted from the light control body 2A is parallel light parallel to the second surface 12, and is incident perpendicularly to the incident surface 10.

Next, as shown in fig. 1B, most of the second incident light LT2A incident on the incident surface 10 is totally reflected by the reflection surface 30 of any one prism 3 of the plurality of prisms 3 provided on the first surface 11, without being reflected by the first surface 11 and the second surface 12. In other words, the light guide member 1 includes a direct optical path L1, and the direct optical path L1 allows the second incident light LT2A incident from the incident surface 10 to be directly reflected by the prism 3 and emitted from the second surface 12. Further, in the present embodiment, the direct optical path L1 includes an optical path of the second incident light LT2A totally reflected by the prism 3. The second incident light LT2A totally reflected on the reflection surface 30 of the prism 3 is emitted from the second surface 12 along an optical path orthogonal to the second surface 12.

Similarly, as shown in fig. 3A and 3B, the first incident light LT1B to the first incident light LT1G emitted from the light sources 4B to 4G are respectively transmitted through the light control bodies 2B to 2G, and are incident on the incidence surface 10 as parallel light, that is, second incident light LT2B to second incident light LT 2G. Here, the second incident light LT2B to the second incident light LT2G are parallel light intersecting the second incident light LT 2A. The second incident light LT2B to the second incident light LT2G are parallel light beams intersecting each other. In other words, the directions of the optical axes P2A to P2G of the second incident light LT2A to second incident light LT2G are different from each other. The directions of the optical axes P2A to P2G are not limited to the mutually different states, and the optical axes P2 having the same direction among the optical axes P2A to P2G may be present as long as the directions of at least two optical axes P2 among the optical axes P2A to P2G are mutually different.

As shown in fig. 3B, the second incident light LT2B to the second incident light LT2G totally reflected by the reflection surface 30 of any one prism 3 of the plurality of prisms 3 provided on the first surface 11 are emitted from the second surface 12 along an optical path orthogonal to the second surface 12.

In the present embodiment, the plurality of prisms 3 are disposed over the entire area of the first surface 11, and therefore the second incident light LT2A to the second incident light LT2G are emitted as the emitted light from the second surface 12 of the light guide member 1 through the direct optical path L1 as described above. Thereby, the second surface 12 emits light, and the emitted light is planar. In the present embodiment, since the directions of the optical axes P2A to P2G are different from each other, the luminance distribution of the second incident light LT2 incident on the first surface 11 becomes uneven. Further, the second incident light LT2 incident on the first surface 11 is emitted perpendicularly to the second surface 12 along the direct optical path L1, and thus the luminance distribution of the emitted light on the second surface 12 becomes uneven. In other words, by controlling the directions of the optical axes P2A to P2G of the second incident light LT2A to second incident light LT2G by the light control bodies 2A to 2G, it is possible to obtain the outgoing light having a desired luminance distribution on the second surface 12.

The advantages of the optical system 100 of the present embodiment including the light control bodies 2A to 2G will be described below with reference to fig. 3A to 3B and fig. 9 to 10.

The directions of the optical axes P2 of the second incident lights LT2 incident on the incident surface 10 from the light controllers (hereinafter, referred to as the light controllers of the comparative example) included in the general optical system (hereinafter, referred to as the optical system 100A of the comparative example) are equal to each other. Fig. 9 shows the luminance distribution of the emitted light in the optical system 100A of the comparative example. In the optical system 100A of the comparative example, a plurality of second incident lights LT2 incident on the incident surface 10 from a plurality of light controllers are parallel lights parallel to each other, and are perpendicularly incident on the incident surface 10. In this case, the luminance distribution of the second incident light LT2 incident on the first surface 11 from the incident surface 10 becomes uniform. Further, the second incident light LT2 incident on the first surface 11 is emitted perpendicularly to the second surface 12 along the direct optical path L1, and thus the luminance distribution AR1 of the emitted light on the second surface 12 becomes uniform as shown in fig. 9. The luminance distribution AR1 shown in fig. 9 and 10 and the luminance distribution AR2 described later schematically represent the luminance distribution of the emitted light on the second surface 12. Here, the luminance distribution AR1 and the luminance distribution AR2 represent portions where the light quantity of the emitted light is relatively larger than the light quantity outside the range of the luminance distribution AR1 and the luminance distribution AR 2.

As in the display system 300 according to the present embodiment, when the optical system 100 including the plurality of light controllers 2 is applied to the head-up display mounted on the moving body B1, the plurality of light controllers 2 are required to unevenly control the luminance distribution of the emitted light on the second surface 12 for the following reasons.

The display surface 312 of the image display unit 310 of the head-up display receives the light emitted from the second surface 12 by the light distribution control unit 14 described later, and displays an image. The display surface 312 is a shape (for example, a rectangular shape) matching the range of the image projected to the user U1, in other words, the shape of the windshield B12. The second face 12 is also arranged in a shape matching the display face 312.

Here, the image displayed on the display surface 312 has a portion in which the luminance distribution changes before being reflected by the windshield B12 and visually recognized by the user U1. Therefore, it is necessary to provide the luminance distribution, which is an optimal image when the user U1 performs visual recognition, to the light emitted from the backlight functioning as the display surface 312.

For example, in the present embodiment, the image displayed on the rectangular display surface 312 is reduced in intensity of light on the upper left of the windshield B12 when viewed from the user U1 before the user U1 views the image. This is a factor that the longer the upper left region of the windshield B12 is, the longer the length of the optical path between the display surface 312 and the eye movement range C1 of the user U1 is, and the light is strongly scattered.

Therefore, in the present embodiment, the directions of the optical axes P2A to P2G are controlled by the light controllers 2A to 2G, respectively, so that the luminance distribution AR2 on the second surface 12 of the outgoing light emitted from the outgoing surface (second surface 12) is controlled to be relatively bright at the lower right and darkened at the upper left as shown in fig. 10. In the present embodiment, the vertical direction viewed from the user U1 of the windshield B12 corresponds to the vertical reversal in the X-axis direction in fig. 9 and 10, and the horizontal direction viewed from the user U1 of the windshield B12 corresponds to the horizontal reversal in the Y-axis direction. Therefore, by controlling the luminance distribution AR2 on the second surface 12 to be relatively bright at the lower right and darkened at the upper left, it is possible to correct the decrease in the intensity of the upper left light of the windshield B12 and to visually recognize an image of uniform brightness by the user U1.

In the present embodiment, in order to obtain the luminance distribution AR2 shown in fig. 10, for example, as shown in fig. 3A, the directions of the optical axes P2A to P2G are controlled so that the slopes of the optical axes P2B to P2G with respect to the optical axis P2A become larger along the X-axis direction from the light source 4A side toward the light source 4G side. As shown in fig. 3B, for example, the directions of the optical axes P2A to P2G are controlled so that the slopes of the optical axes P2B to P2F with respect to the optical axis P2A are equal when viewed from the X-axis direction, and the slope of the optical axis P2G with respect to the optical axis P2A is larger than the slope of the optical axes P2B to P2F with respect to the optical axis P2A. The directions of the optical axes P2A to P2G can be changed appropriately according to the desired luminance distribution AR 2.

(2.4) light controlling body

Next, the shape and function of the light control body 2 according to the present embodiment will be described in detail with reference to fig. 2 and fig. 11 to 13.

The light control body 2 includes an incidence lens 21. In the present embodiment, the incident lenses 21 included in the light control bodies 2B to 2G include, for example, a plurality of lens portions 22 having mutually different lens characteristics such as a distribution of curvatures on the lenses. Thereby, the light control bodies 2B to 2G can change the direction of the optical axis P2 from the direction of the optical axis P1.

In the incident lens 21 having a curvature distribution on the lens that is rotationally symmetrical with respect to the central axis of the lens, for example, which is provided in the light control body 2A, when the first incident light LT1 having the optical axis P1 that coincides with the normal L21 of the main incident surface 211 is incident, the direction of the optical axis P2 of the second incident light LT2 is the same direction as the direction of the optical axis P1. The incident lens 21 provided in the light control body 2A may not be rotationally symmetrical with respect to the central axis of the lens as long as the direction of the optical axis P2 can be controlled to be the same as the direction of the optical axis P1.

On the other hand, by providing the plurality of lens portions 22 with different curvature distributions in each of the light control bodies 2B to 2G, the second incident light LT2, which is parallel light having the optical axis P2 different from the direction of the optical axis P1, can be made incident on the incident surface 10.

As shown in fig. 11, in the present embodiment, for example, the incident lens 21 included in the light control body 2B to the light control body 2G includes four lens portions 22 (first lens portion 221 to fourth lens portion 224). The light control bodies 2B to 2G respectively make the first incident light LT1, which is respectively made to enter the first lens portion 221 to the fourth lens portion 224 from the light source 4, enter the incident surface 10.

Here, the areas of the first lens portion 221 to the fourth lens portion 224 viewed from the direction of the optical axis P1 of the first incident light LT1 are equal. The first lens portion 221 to the fourth lens portion 224 are each provided in a fan shape that extends in the outer circumferential direction around a point Q1 at which the incident lens 21 intersects the optical axis P1. The first lens portion 221 and the third lens portion 223, which are disposed opposite to each other in the radial direction of a circle centered on the point Q1, are, for example, point-symmetrical with respect to the point Q1 when viewed from the direction of the optical axis P1. The second lens portion 222 and the fourth lens portion 224, which are disposed opposite to each other in the radial direction of a circle centered on the point Q1, are, for example, point-symmetrical with respect to the point Q1 when viewed from the direction of the optical axis P1. In other words, the incident lens 21 is equally divided into the first lens portion 221 to the fourth lens portion 224 by a plurality of (two in the present embodiment) planes PL2, PL3 intersecting each other. In the present embodiment, a straight line formed by the two intersecting planes PL2 and PL3 coincides with the optical axis P1. Further, if the areas viewed from the direction of the optical axis P1 are equal, the first lens portion 221 and the third lens portion 223 may not be point-symmetrical with respect to the point Q1. Further, if the areas viewed from the direction of the optical axis P1 are equal, the second lens portion 222 and the fourth lens portion 224 may not be point-symmetrical with respect to the point Q1.

Further, the first lens portion 221 to the fourth lens portion 224 are each smoothly continuous. In other words, the curvature of the incident lens 21 is greater than 0 at the boundary of each of the first lens portion 221 to the fourth lens portion 224.

However, as shown in fig. 2, the incident lens 21 is provided with a refractive lens 23 and a reflective lens 24. In the present embodiment, the refractive lens 23 is formed in a circular shape when viewed from the direction of the optical axis P1. The reflection lens 24 is formed in a ring shape surrounding the outer periphery of the refractive lens 23 in a circular shape throughout the entire periphery.

The refractive lens 23 has a main entrance face 211. The main incidence surface 211 is disposed so as to face the light source 4, and at least a part of the first incident light LT1 from the light source 4 is incident on the refractive lens 23 from the main incidence surface 211. Here, since the first incident light LT1 is light radially expanded from the light source 4, at least a part of the first incident light LT1 incident on the refractive lens 23 is refracted at the main incident surface 211 according to the incident angle of the light beam to the main incident surface 211. At least a part of the first incident light LT1 refracted at the main incident surface 211 is incident on the incident surface 10 as at least a part of the second incident light LT2, which is parallel light.

The reflection lens 24 has a sub-incident surface 212 and an outer peripheral surface 213.

The sub-incident surface 212 faces the normal L21 of the main incident surface 211. In the present embodiment, the sub incident surface 212 is provided in a circular ring shape surrounding the main incident surface 211. The sub-incident surface 212 is not limited to a circular ring shape surrounding the main incident surface 211, and may be located at least in a part of the periphery of the main incident surface 211. The sub-incident surface 212 may be parallel to the normal line L21 of the main incident surface 211 (in other words, may not be inclined), or may be inclined.

The outer peripheral surface 213 is located on the opposite side of the normal line L21 of the main incidence surface 211 as viewed from the sub incidence surface 212.

At least a part of the first incident light LT1 is incident on the reflection lens 24 from the sub-incident surface 212. At least a portion of the first incident light LT1 incident on the reflection lens 24 is refracted at the sub-incident surface 212 according to the incident angle of the light ray with respect to the sub-incident surface 212. At least a part of the first incident light LT1 refracted at the sub-incident surface 212 is totally reflected by the outer peripheral surface 213, and is incident on the incident surface 10 as at least a part of the second incident light LT 2.

For example, as shown in fig. 12, in the case of controlling the first incident light LT1 such that the optical axis P2 is located on the optical axis P1 by the light control body 2A, at least a part of the first incident light LT1A refracted at the main incident surface 211 is perpendicularly incident on the incident surface 10 as parallel light, that is, at least a part of the second incident light LT 2A. At least a part of the first incident light LT1A refracted at the sub-incident surface 212 is totally reflected by the outer peripheral surface 213, and is vertically incident on the incident surface 10 as at least a part of the second incident light LT 2A.

Further, for example, as shown in fig. 13, in the case of controlling the first incident light LT1 such that the optical axis P1 intersects the optical axis P2 (forming an angle of 0 degrees or more), for example, the light control body 2G, at least a part of the first incident light LT1G refracted at the main incident surface 211 is incident obliquely with respect to the incident surface 10 as parallel light, that is, at least a part of the second incident light LT 2G. At least a part of the first incident light LT1G refracted at the sub-incident surface 212 is totally reflected by the outer peripheral surface 213, and is obliquely incident on the incident surface 10 as at least a part of the second incident light LT 2G. Here, at least a part of the first incident light LT1G is refracted in the same direction, for example, regardless of the position on the main incident surface 211 of the light control body 2G. Further, at least a part of the first incident light LT1G is reflected in, for example, the same direction regardless of the position on the outer peripheral surface 213. Further, at least a portion of the first incident light LT1G is, for example, in the same direction as the direction in which the main incident surface 211 is refracted and the direction in which the first incident light LT is reflected at the outer peripheral portion 213. The lens portion 21 may be configured to refract at least a part of the first incident light LT1G in different directions depending on the position on the main incident surface 211, or may be configured to reflect at least a part of the first incident light LT1G in different directions depending on the position on the outer peripheral surface 213. The lens portion 21 may be configured such that at least a portion of the first incident light LT1G is refracted in the main incident surface 211 in a direction different from the direction reflected by the outer peripheral portion 213.

Here, as described above, the incident lens 21 included in the light control bodies 2B to 2G includes the first lens portion 221 to the fourth lens portion 224. As described above, the incident lens 21 includes the refractive lens 23 and the reflective lens 24 (see fig. 2). The refractive lens 23 is formed in, for example, a circular shape when viewed from the direction of the optical axis P1. The reflection lens 24 is formed in, for example, a circular ring shape surrounding the outer periphery of the circular refractive lens 23 over the entire periphery. Accordingly, as shown in fig. 11, the first to fourth lens portions 221 to 224 include, for example, refractive lens portions (first to fourth refractive lens portions 231 to 234) which are part of the refractive lens 23 having a circular shape, and reflective lens portions (first to fourth reflective lens portions 241 to 244) which are part of, for example, the annular reflective lens 24 surrounding the outer periphery of the refractive lens 23. The first to fourth refractive lens portions 231 to 234 each have first to fourth main incidence surfaces 2111 to 2114 as a part of the main incidence surface 211. The first to fourth reflection lens portions 241 to 244 have first to fourth sub-incident surfaces 2121 to 2124 as a part of the sub-incident surface 212 and first to fourth outer peripheral surfaces 2131 to 2134 as a part of the outer peripheral surface 213, respectively.

At least a part of the first incident light LT1 incident on the first to fourth refractive lens portions 231 to 234 from the first to fourth principal incident surfaces 2111 to 2114 is refracted at the first to fourth principal incident surfaces 2111 to 2114, respectively. At least a part of the first incident light LT1 refracted at each of the first to fourth principal incident surfaces 2111 to 2114 is incident on the incident surface 10 as at least a part of the second incident light LT2 which is parallel light.

At least a part of the first incident light LT1 incident on the first to fourth reflection lens sections 241 to 244 from the first to fourth sub-incident surfaces 2121 to 2124 is refracted at the first to fourth sub-incident surfaces 2121 to 2124, respectively. At least a part of the first incident light LT1 refracted at the first to fourth sub-incident surfaces 2121 to 2124 is totally reflected by the first to fourth outer peripheral surfaces 2131 to 2134, respectively, and is incident on the incident surface 10 as at least a part of the second incident light LT 2.

In other words, at least a part of the first incident light LT1 incident on the first to fourth lens portions 221 to 224 becomes the second incident light LT21 to second incident light LT24, which is at least a part of the second incident light LT2, respectively, and the second incident light LT21 to second incident light LT24 is incident on the incident surface 10 from the first to fourth lens portions 221 to 224, respectively.

Here, the second incident light LT21 to the second incident light LT24 are, for example, parallel light. The optical axes of the second incident light LT21 to the second incident light LT24 are, for example, parallel to each other. In other words, the second incident light LT2 that is incident on the incident surface 10 by the light control bodies 2B to 2G includes, for example, second incident light LT21 to second incident light LT24 that are parallel to each other.

(2.5) light distribution control portion

Next, the light distribution control unit 14 will be described in detail with reference to fig. 4.

In the present embodiment, at least one of the first surface 11 and the second surface 12 has the light distribution control portion 14. The light distribution control unit 14 controls the distribution of the emitted light extracted from the second surface 12 serving as the emission surface. The term "distribution of emitted light" as used herein refers to the spread of emitted light. In the present embodiment, as an example, the light distribution control unit 14 is provided on the second surface 12. Further, in the present embodiment, the light distribution control unit 14 and the light guide member 1 are integrated into an integrally molded product. In other words, in the present embodiment, the light guide member 1 and the light distribution control portion 14 are integrally molded articles, and are in an integral inseparable relationship.

In summary, in the present embodiment, the light guide member 1 includes the direct optical path L1, and the direct optical path L1 allows the second incident light LT2 incident into the light guide member 1 from the incident surface 10 to be emitted from the second surface 12 by only 1 reflection of the prism 3 inside the light guide member 1. Therefore, the shapes of the first surface 11 and the second surface 12 do not contribute to the light guiding of the second incident light LT2 inside the light guiding member 1, and even if the light distribution control portion 14 is provided on the first surface 11 or the second surface 12, the light guiding performance of the light guiding member 1 is not easily deteriorated.

Specifically, the light distribution control unit 14 in the present embodiment includes a lens. In other words, the light distribution control section 14 has a function as a lens of an optical element for refracting light to diverge or converge. In this way, the light distribution control unit 14 can control the light distribution by refracting, dispersing, or converging the light emitted from the second surface 12, which is the emission surface.

More specifically, the light distribution control unit 14 includes a multi-lens composed of a plurality of groups of lenslets 141. In the present embodiment, the plurality of lenslets 141 are each formed in a semi-cylindrical shape. The plurality of lenslets 141 are arranged in the X-axis direction. Here, the plurality of lenslets 141 are formed without gaps in the entire region of the second face 12. A multi-lens composed of a group of a plurality of lenslets 141 of such a shape constitutes a so-called cylindrical lens.

For example, in the present embodiment, the light distribution control unit 14 controls the light distribution of the outgoing light so that the outgoing light is projected to the display surface 312 of the image display unit 310 with an appropriate size while maintaining the relative brightness distribution on the second surface 12 of the outgoing light.

(3) Modification examples

A modification of the above embodiment will be described below. The same reference numerals are given to the components common to the above embodiments, and the description thereof will be omitted as appropriate. The configurations of the modification described below can be appropriately combined with the configurations described in the above-described embodiments.

(3.1) modification 1

In the optical system 100 of the above embodiment, the refractive lens 23 is formed in a circular shape when viewed from the direction of the optical axis P1. The reflection lens 24 is formed so as to surround the entire circumference of the circular refractive lens 23. On the other hand, as shown in fig. 14, the optical system 100 of modification 1 is different from the above-described embodiment in that the refractive lens 23 is formed in a circular shape (a lack of a circle) partially lacking when viewed from the direction of the optical axis P1. The refractive lens 23 of modification 1 includes an arc portion 235 and a chord portion 236 on the outer periphery of the lacking circle shape, and the reflective lens 24 is formed along the arc portion 235 of the refractive lens 23.

In this case, among the refractive lenses 23A to 23G included in each of the light control bodies 2A to 2G, the refractive lenses 23 adjacent to each other in the X-axis direction have a common chord portion 236, and are continuous in the common chord portion 236.

(3.2) modification 2

In the optical system 100 of the above embodiment, the optical axes of the second incident light LT21 to the second incident light LT24 are parallel to each other. On the other hand, the optical system 100 of modification 2 is different from the above-described embodiment in that directions of at least two optical axes among the optical axes of the second incident light LT21 to the second incident light LT24 are different from each other. In other words, the light control body 2 of modification 2 can control the emission directions of the second incident light LT21 to the second incident light LT24, which are parallel lights, respectively. As a result, the luminance distribution of the outgoing light on the second surface 12 can be controlled more finely than in the case where the outgoing direction of the second incoming light LT2 is controlled for each of the plurality of light controllers 2 in the above-described embodiment.

(3.3) other modifications

The first refractive lens portions 231 to 234 and the first reflective lens portions 241 to 244 may control the refractive directions of the first incident light LT1 incident on the respective lens portions, and the refractive directions of the first incident light LT1 incident on the first refractive lens portions 231 to 234 and the first reflective lens portions 241 to 244 may not be the same.

The first surface 11 may be a surface perpendicular to the incident surface 10, and the second surface 12 may be a surface inclined with respect to the X-Y plane, not perpendicular to the incident surface 10. The first surface 11 and the second surface 12 may each be a surface inclined with respect to the X-Y plane, not orthogonal to the incident surface 10.

The light guide member 1 may include the direct optical path L1, and the entirety of the second incident light LT2 incident from the incident surface 10 does not necessarily pass through the direct optical path L1. That is, the light guide member 1 may include, for example, an indirect optical path that is reflected by the prism 3 and then emitted from the second surface 12 after being reflected by the first surface 11 or the second surface 12 more than once.

In addition, the first surface 11 may be provided with only one prism 3 instead of the plurality of prisms 3. In this case, the prism 3 may have a plurality of reflection surfaces 30 formed over the entire surface of the first surface 11 and having different inclination angles.

In embodiment 1, the prism 3 is formed by processing the first surface 11 of the light guide member 1, but the present invention is not limited to this. For example, the prism 3 may be provided on the first surface 11 by attaching a prism sheet on which the prism 3 is formed to the first surface 11. In this case, the prism sheet may be formed with one prism 3, or may be formed with a plurality of prisms 3.

The prism 3 is not limited to a concave shape with respect to the first surface 11, in other words, a shape recessed from the first surface 11, but may be a convex shape with respect to the first surface 11, in other words, a shape protruding from the first surface 11.

The end surface 13 of the light guide member 1 may be an inclined surface inclined with respect to the incident surface 10 such that the distance from the incident surface 10 in the Y-axis direction is greater on the second surface 12 side than on the first surface 11 side. By the end surface 13 being such an inclined surface, even if a part of the second incident light LT2 incident from the incident surface 10 reaches the end surface 13 without being incident on the first surface 11, a part of the second incident light LT2 can be emitted from the second surface 12. That is, when a part of the second incident light LT2 incident from the incident surface 10 is incident on the end surface 13, a part of the second incident light LT2 is totally reflected at the end surface 13 toward the second surface 12, and is emitted from the second surface 12. As a result, in addition to the light emitted from the second surface 12 to the outside of the light guide member 1 through the direct optical path L1, a part of the second incident light LT2 reaching the end surface 13 can be effectively extracted from the second surface 12.

The light distribution control unit 14 may be provided on at least one of the first surface 11 and the second surface 12 to control the distribution of the light extracted from the second surface 12. That is, in the above embodiment, the light distribution control unit 14 is provided on the second surface 12 as the emission surface, but the configuration is not limited to this, and the light distribution control unit 14 may be provided on the first surface 11, or may be provided on both the first surface 11 and the second surface 12. Further, in the above embodiment, the light distribution control unit 14 and the light guide member 1 are integrated into an integrally molded product, but the present invention is not limited to this embodiment. For example, the light distribution control unit 14 may be provided on the second surface 12 by attaching a light distribution sheet having the light distribution control unit 14 formed thereon to the second surface 12.

The light distribution control unit 14 is not limited to a lens, and may be a diffusion sheet, a prism, a diffraction grating, or the like, for example. The light distribution control unit 14 is not necessarily configured for the optical system 100, and can be omitted appropriately.

The mobile body B1 on which the display system 300 is mounted is not limited to a motor vehicle (passenger car), and may be a large vehicle such as a truck or a bus, a two-wheeled vehicle, a trolley, an electric cart, a construction machine, an airplane, a ship, or the like.

The display system 300 is not limited to a structure that displays a virtual image as in a head-up display. For example, display system 300 may be a liquid crystal display or a projector device. The display system 300 may be a display of an automobile navigation system, an electronic mirror system, or a multifunction information display mounted on the mobile body B1 1.

The illumination system 200 is not limited to the configuration used for the display system 300, and may be used for industrial applications such as resin curing and plant cultivation, illumination applications including guide lamps, and the like.

(4) Summary

As described above, the optical system (100) according to the first aspect includes the light guide member (1), the prism (3), and the plurality of light control bodies (2). The light guide member (1) has an incidence surface (10) on which light is incident, and a first surface (11) and a second surface (12) that face each other. The second surface (12) of the light guide member (1) is a light exit surface. The prism (3) is provided on the first surface (11) and reflects light passing through the inside of the light guide member (1) toward the second surface (12). A plurality of light control bodies (2) are located between the light source (4) and the entrance face (10). The plurality of light control bodies (2) control light outputted from the light source (4) and incident on the incident surface (10). The plurality of light control bodies (2) are each provided with an incidence lens (21). The plurality of light control bodies (2) respectively make the light which is incident on the incidence lens (21) from the light source (4) incident on the incidence surface (10). At least two light control bodies (2) among the plurality of light control bodies (2) are different from each other in the direction of the optical axis of light incident on the incident surface (10).

According to this aspect, the optical axis of the light incident on the incident surface (10) is controlled for each of the plurality of light control bodies (2), whereby the luminance distribution of the light emitted from the second surface (12) can be controlled.

In the optical system (100) according to the second aspect, in the first aspect, an angle formed by optical axes of light incident on the incident surface (10) by the at least two light control bodies (2) is greater than 0 degrees and 15 degrees or less.

According to this aspect, the luminance distribution of the light emitted from the second surface (12) can be controlled within an appropriate range on the second surface (12).

In the optical system (100) according to the third aspect, in the first or second aspect, the incident lens (21) includes a plurality of lens portions (22) having different lens characteristics from each other. The plurality of light control bodies (2) respectively make the light respectively entering the plurality of lens parts (22) from the light source (4) enter the incidence surface (10). At least two lens parts (22) of the plurality of lens parts (22) respectively make different directions of optical axes of light entering the incidence surface (10).

According to this aspect, the luminance distribution of the light emitted from the second surface (12) can be controlled more precisely.

In the optical system (100) according to the fourth aspect, in the third aspect, the incident lens (21) is divided into a plurality of lens portions (22) by a plurality of planes or the like intersecting each other.

In the optical system (100) according to the fifth aspect, in the third or fourth aspect, the plurality of lens portions (22) are each smoothly continuous.

According to this aspect, light incident on the plurality of lens sections (22) from the light source (4) can be efficiently incident on the incident surface (10).

In the optical system (100) according to the sixth aspect, in any one of the third to fifth aspects, the incident lens (21) has four lens portions (22).

In the optical system (100) according to the seventh aspect, in any one of the third to sixth aspects, the plurality of lens portions (22) includes a refractive lens portion that refracts light and a reflective lens portion that reflects light.

In the optical system (100) according to the eighth aspect, in any one of the first to seventh aspects, the light guide member (1) includes a direct optical path (L1), and the direct optical path (L1) directly reflects light incident from the incident surface (10) by the prism (3) and emits the light from the second surface (12).

According to this aspect, the light extraction efficiency can be improved.

An illumination system (200) according to a ninth aspect is provided with: an optical system (100) according to any one of the first to eighth aspects; and a light source (4) that outputs the light source (4) that is incident on the incident surface (10).

According to this aspect, the luminance distribution of the light emitted from the second surface (12) can be controlled.

A display system (300) according to a tenth aspect includes: a lighting system (200) according to a ninth aspect; and a display (5) that receives light emitted from the illumination system (200) and displays an image.

A mobile body (B1) according to an eleventh aspect is provided with the display system (300) according to the tenth aspect; and a mobile body (B11) on which the display system (300) is mounted.

According to the present disclosure, there is an advantage in that unevenness in brightness of an image visually recognized by a user can be reduced.

Description of the reference numerals-

1. Light guide member

2. Light control body

3. Prism

4. Light source

5. Display device

10. Incidence plane

11. First surface

12. A second surface

21. Incidence lens

22. Lens part

100. Optical system

200. Lighting system

300. Display system

B1 Moving body

B11 Moving body main body

L1 direct optical path.

Claims

1. An optical system is provided with:

a light guide member having an incident surface on which light is incident, and a first surface and a second surface which are opposite to each other, the second surface being a light emitting surface;

A prism provided on the first surface and configured to reflect light passing through the inside of the light guide member toward the second surface; and

a plurality of light control bodies positioned between the light source and the incident surface, for controlling light outputted from the light source and incident on the incident surface,

the plurality of light controlling bodies are respectively provided with an incidence lens,

the plurality of light controlling bodies respectively make the light incident from the light source to the incidence lens incident to the incidence surface,

at least two light control bodies among the plurality of light control bodies respectively make different directions of optical axes of light incident on the incident surface.

2. The optical system according to claim 1, wherein,

the angle formed by the optical axes of the light which is respectively incident on the incidence surface by the at least two light control bodies is more than 0 degree and less than 15 degrees.

3. An optical system according to claim 1 or 2, wherein,

the incidence lens includes a plurality of lens portions having lens characteristics different from each other,

the plurality of light control bodies respectively make the light respectively incident to the plurality of lens parts from the light source respectively incident to the incidence surface,

at least two lens portions among the plurality of lens portions respectively have directions of optical axes of light incident on the incident surface different from each other.

4. An optical system according to claim 3, wherein,

the incident lens is divided into a plurality of lens portions by a plurality of planes intersecting each other.

5. An optical system according to claim 3 or 4, wherein,

the plurality of lenses are each smoothly continuous.

6. The optical system according to any one of claims 3 to 5, wherein,

the incidence lens has four lens portions.

7. The optical system according to any one of claims 3 to 6, wherein,

the plurality of lens portions include a refractive lens portion that refracts light and a reflective lens portion that reflects light.

8. The optical system according to any one of claims 1 to 7, wherein,

the light guide member includes a direct optical path that allows light incident from the incident surface to be directly reflected by the prism and to exit from the second surface.

9. An illumination system is provided with:

the optical system of any one of claims 1-8; and

and a light source for outputting light incident on the incident surface.

10. A display system is provided with:

the lighting system of claim 9; and

and a display for receiving the light emitted from the illumination system and displaying an image.

11. A mobile body is provided with:

the display system of claim 10; and

and a mobile body on which the display system is mounted.